steadfast
3 occurrences across the corpus
KJV Apocrypha (Catholic Deuterocanon)
Additions to Esther 13:3
Now when I asked my counsellors how this might be brought to pass, Aman, that excelled in wisdom among us, and was approved for his constant good will and steadfast fidelity, and had the honour of the second place in the kingdom,
Wisdom of Solomon 7:23
Kind to man, steadfast, sure, free from care, having all power, overseeing all things, and going through all understanding, pure, and most subtil, spirits.
OT Pseudepigrapha
The Letter of Aristeas 8:22
For the mind mostly busies itself in sleep with the same things with, which it occupies itself when awake. And he who has all his thoughts and actions set towards the noblest ends establishes himself in righteousness both when he is awake and when he is asleep. Wherefore. you must be steadfast in the constant discipline of self.